//! @brief Solana builtin helper macros
/// Convenience macro to declare a builtin
///
/// bs58_string: bs58 string representation the program's id
/// name: Name of the program
/// entrypoint: Program's entrypoint, must be of `type Entrypoint`
/// id: Path to the program id access function, used if this macro is not
/// called in `src/lib`
///
/// # Examples
///
/// ```
/// use std::str::FromStr;
/// // wrapper is used so that the macro invocation occurs in the item position
/// // rather than in the statement position which isn't allowed.
/// mod item_wrapper {
/// use solana_sdk::keyed_account::KeyedAccount;
/// use solana_sdk::instruction::InstructionError;
/// use solana_sdk::pubkey::Pubkey;
/// use solana_sdk::declare_builtin;
///
/// fn my_process_instruction(
/// program_id: &Pubkey,
/// keyed_accounts: &[KeyedAccount],
/// instruction_data: &[u8],
/// ) -> Result<(), InstructionError> {
/// // Process an instruction
/// Ok(())
/// }
///
/// declare_builtin!(
/// "My11111111111111111111111111111111111111111",
/// solana_my_program,
/// my_process_instruction
/// );
///
/// # }
/// # use solana_sdk::pubkey::Pubkey;
/// # use item_wrapper::id;
/// let my_id = Pubkey::from_str("My11111111111111111111111111111111111111111").unwrap();
/// assert_eq!(id(), my_id);
/// ```
/// ```
/// use std::str::FromStr;
/// # // wrapper is used so that the macro invocation occurs in the item position
/// # // rather than in the statement position which isn't allowed.
/// # mod item_wrapper {
/// use solana_sdk::keyed_account::KeyedAccount;
/// use solana_sdk::instruction::InstructionError;
/// use solana_sdk::pubkey::Pubkey;
/// use solana_sdk::declare_builtin;
///
/// fn my_process_instruction(
/// program_id: &Pubkey,
/// keyed_accounts: &[KeyedAccount],
/// instruction_data: &[u8],
/// ) -> Result<(), InstructionError> {
/// // Process an instruction
/// Ok(())
/// }
///
/// declare_builtin!(
/// solana_sdk::system_program::ID,
/// solana_my_program,
/// my_process_instruction
/// );
/// }
///
/// # use item_wrapper::id;
/// assert_eq!(id(), solana_sdk::system_program::ID);
/// ```